American Community Survey Multi-Year Estimates Pennsylvania Data Users’ Perspectives

Multi-Year Estimates Background Background Geographic Matters Geographic Matters –Availability –Shortcuts Table Availability Table Availability Comparability Comparability Accuracy and Margins of Error Accuracy and Margins of Error

Background The Pennsylvania State Data Center answers several thousand data requests per year. The Pennsylvania State Data Center answers several thousand data requests per year. –An extremely wide range of expertise: from clients without a computer to professional data analysts. Clients come from many constituencies. Clients come from many constituencies. –State Legislators, State Government, Media, Planners, Non-Profits, Educators (and many more).

Geographic Matters The advent of 3-Year Multi-Year Estimates has been a boon to many data users across the commonwealth. The advent of 3-Year Multi-Year Estimates has been a boon to many data users across the commonwealth. –61 of Pennsylvania’s 67 counties are covered by ACS 3-Year Estimates. Those missing counties are the single biggest obstacle to many data users. Those missing counties are the single biggest obstacle to many data users. –i.e., I need data for all counties.

Geographic Shortcuts Other Geographies can stand in for groups of counties to complete county coverage. Other Geographies can stand in for groups of counties to complete county coverage. –MSAs –PUMAs and Super-PUMAs.  Data Users need to be warned not to subtract missing counties from MSAs or PUMAs in an attempt to ‘back out’ the missing geographies. Other geographies can offer complete state coverage: Other geographies can offer complete state coverage: –Congressional Districts

Geography 3-year Estimates cannot supplant the (eventual) geographic coverage of 5-year estimates. 3-year Estimates cannot supplant the (eventual) geographic coverage of 5-year estimates. –Often, the answer must be “wait until 2010.”

Table Availability Increased Table Availability is one of the most popular benefits of Multi-Year Estimates. Increased Table Availability is one of the most popular benefits of Multi-Year Estimates. –Data Users have been surprised and annoyed by the dynamic filtering of tables. –Moving from 1-Year Estimates to 3-Year Estimates has helped these data users include tables at risk of being filtered.

Table Availability The lack of a Advanced Query-like system for ACS has greatly restricted clients with very specific data needs. The lack of a Advanced Query-like system for ACS has greatly restricted clients with very specific data needs. –PaSDC has begun using ACS Multi-Year PUMS for more complex and specific requests.  Unfortunately, a much more time-consuming and laborious effort than using Detailed Tables.  At the expense of much geographic detail.

Comparability Data users are unsure of how ACS data can be compared to Census 2000 data. Data users are unsure of how ACS data can be compared to Census 2000 data. –The ACS web site is a useful resource. More detailed guidance is still lacking. More detailed guidance is still lacking. –What to do with ‘Compare with Caution’?  Especially when comparatively benign comparisons (e.g., Age) and more worrisome comparisons (e.g., Income/Poverty) are both ‘Compare with Caution.’

Accuracy and Margins of Error By far, the most common complaints from data users regard the margins of error. By far, the most common complaints from data users regard the margins of error. –How do we determine reliability? (i.e., What do they mean?) –How do we display them? (Can’t always double the number of columns in a publication.) –How to derive new ones for manipulated tables? (Most data users balk at the first sight of a square root sign!)

Accuracy and Margins of Error Unfortunately, the most common reaction and use of margins of error (among data users) is to ignore them completely and delete them from published tables. Unfortunately, the most common reaction and use of margins of error (among data users) is to ignore them completely and delete them from published tables. More tools are needed to make ACS margins easier and more accessible to work with. (More collapsed tables!) More tools are needed to make ACS margins easier and more accessible to work with. (More collapsed tables!)

Best Advice for ACS Data Users Choosing tables and picking geographies is much more important (and difficult!) with ACS data than with Census Choosing tables and picking geographies is much more important (and difficult!) with ACS data than with Census –Principle: the more detailed data you need, the higher level of geography you should expect. –Corollary: the smaller geography you need, the simpler table you should expect to use.

Kevin McCullough Senior Research Coordinator Pennsylvania State Data Center